1. This contract provides the NIDA Division of Therapeutics and Medical Consequences with reports in which the Contractor assesses the pharmacological specificity and potential toxicity of lead compounds by screening at a large number of biological targets. 2. This contract will also support studies to determine the affinity (IC50, Ki) and/or function (EC50, IC50) of test compounds for receptors at specified biological targets indicated by compound profiling or other sources. 3. This contract will provide a way to screen additional compounds, possibly large compound libraries, at one or more receptors or transporters in order to determine biological activity, with the objective of discovering specific receptor or transporter ligands with novel chemical structures. 4. This contract will provide assays to assess predictive toxicology in key areas that could indicate a candidate compound would have difficulties in the drug development process. 5. This contract will allow development of in vitro assays at targets that may be of importance in the development of compounds for the treatment of drug abuse and its consequences.